Improvement in air-compressors



NLO. 215,540.`

J. B. PITCI-IlORD.4 Air-Gom-pressor.

PatentevdMay 20,1879.

Nv FEIERS, FHOTD-LITHUGRAPHER. WASHINGTON. D. C.

UNITED SfrATHsPA'rHNT OND-fronc y JOHN B. PITOHFORD, OF GOLD HILL, NEVADA.

IMPROVEMENT IN AIR-COMPRESSORS.

Specification forming part of Letters Patent No. 215,540, dated May 20, 1879; application led February 26, 1879.

To all whom it may concern:

Be it known that I, JOHN B. PrroHFORD, of Gold Hill, county of Storey, and State of Nevada, have invented an Im proved Air-Compressor; and I hereby declare that the following is afulhclear, and exact description thereof, reference being made to the accompanying drawings.

My invention relates to an improved aircompressor; and my improvements consist, first, in a peculiar construction and Operation of the dischargeyalves, whereby, by suitable connection to the stem of said valves, which operate in sleeves or cylinders, the supply of water to the air-cylinder is automatically regulated, and no water will be used in the cylinder unless the compressor is workin g, but not then unt-il the air-valve opens, which is the time it is needed.

It further consists in the method of placing the vinlet-valves and the drip-plates connected with them, and also in combining brass rings and hemp packing on the piston, so as to carry the moisture all around the piston in the aircylinder by capillary attraction, and thereby keep it lubricated.

Figure l represents a longitudinal section of the air-cylinder and piston. Fig. 2 is an end elevation of the air-cylinder.

Let A represent a piston, which is made of cast-iron, with a follower, G, of the same material. A space, a, `is left for hemp packing, which is retained by the follower. Each side of the hemp packing are two or more grooves, turned and tted with brass snaprings n a. A dovetailed recess is formed on w each side of the piston,into each of which is tted a plate of rubber, H, as shown. This rubber plate projectsan eighth of an inch, or more, beyond any part of the piston, as shown, so that the piston can be run clear to the end of the stroke, and the rubber may touch the heads of the cylinder at each end without any danger of breaking them, and by this means all the air is expelled from the cylinder at each stroke of the piston.

The inletvalves B B are made to open into the cylinder, and when closed are flush with the cylinderhead inside, leaving no space for air. They are made of metal, faced with vulcanized rubber. Outside the inlet-valves is a to the 'discharge-pipe I), which is cast with the cylinder. An air-pipe, K, leading to the air-receiver, is attached to the pipe D.

l The discharge-valves C C close iush with the cylinder-head inside. Each of these valves is constructed with a guidestem, d, on the back of it, which acts Aas a piston-valve, sliding back and forth in the sleeve b, forming part of the cover. A water-pipe, E, is connected to this sleeve in such a manner that the passage can be closedior opened by the action of the piston-valve, as hereinafter described.

The pipe E, connected 'toone side of the sleeve b, leads from the water-supply, which is intended to have a greater pressure than that of the air. The jet-pipe F is connected from the sleeve b to a jetin any suitable place in the cylinder-cover.

From what has been described, it will be seen that when the airdischarge valve is closed the piston has also shut off the water by the ring or valve c on the valve-stem d, closing the supplypipe E. No water will therefore be used in the cylinder unless the compressor is working, and even then it will not be used until the airvalve C opens, which is just the time that it is needed, and that will only be for about one-fifth of the stroke of the piston when making seventy pounds of air. The small piston water-valve c, being balanced, offers very little resistance to the opening of -the air-discharge valve G, on the stem of which it is placed. A

Fig. lis a longitudinal section of a governor which is constructed and operated in such a manner as to regulate the speed of the engine by the pressure of the airin the air-receiver.

The governor-valve Al is attached to the stem F in the usual manner, and plays in a chamber or cylinder, G', with which the steampipe D' connects. C C are pipes leading to and from the air-receiver, and B is a piston playing in a chamber, H', and actuated by the pressure of the air 1n the air-receiver, which pressure is communicated to'the chamber H through the pipes C C.

Adjusting-springs E E are intended for regulating the governor. These springs are adjusted so as to set the spindle or stem, on which the governor valve and pist-011 are placed, up or down, and maintain the piston B in a certain position in its chamber under any desired pressure. Any excess, however, of that specified pressure will push the piston B and stem F' down, and thus commence to close the throttle-valve A', thereby reducing the speed of the engine.

This governor is placed in position, as shown, on the steam-chest of the steam-cylinder L. This steam-cylinder is made in the usual way.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The improvement in air-compressors, consisting in the piston A and its follower Gr, with their metallic packing snap-rings n a, in combination with the hemp or other porous packing fitted into the central groove, a, so as to carry the moisture around the piston by capillary attraction, and thus lubricate it, substantially as herein described.

2. The discharge-valves C, with their stems d and valves c, in combination with the pipe E and jet-tube ot' an air-compressor, whereby an intermittent jet of Water is discharged into the cylinder, substantially as and for the purpose herein described.

In witness whereof I have hereunto set my hand.

JOHN B. PITGHFORD.

Witnesses:

. M. G. FooTE, W. G. HYDE. 

